Scrapie is a Transmissible Spongiform Encephalopathies (TSE) disease, of the same family as Bovine Spongiform Encephalopathy (BSE) in cattle. They are infectious wasting diseases which affect the nervous system. The genetic makeup (genotype) of a sheep has a profound effect on which sheep may become infected.
Scrapie genotype in sheep is stated as a pair of three letter alleles (xxx/xxx). Each letter in the allele relates to a codon position in the relevant DNA. The three codons tested in the UK and the resulting five alleles are:
Scrapie genotype falls into one of 5 types, called Type / R 1 to 5. (Also known as G1 to G5 in some European countries).
The good news is that no Shropshire has been found with the VRQ allele so no Shropshires fall into Type R4 or Type R5.
Scrapie genotype and breeding –
A lamb gets an allele from each parent, so the laws of probability come into play in predicting scrapie genotype in progeny. E.g ARR/ARR crossed with ARR/ARQ can give ARR/ARR (50%), ARR/ARQ (50%). ARR/ARQ with ARR/ARQ can give ARR/ARR (25%); ARR/ARQ (50%), ARQ/ARQ (25%).
Scrapie genotyping your sheep –
There are several laboratories that offer genotype testing where you can sample your own sheep, including:
The SSBA does not recommend any one lab or testing method over any others. The SSBA has looked at whether we could put together a society run scheme (like the Charollais society) but our volumes are not high enough to justify it to the labs or recover the admin costs.
Pricing per test varies by lab and by number tested. At March 2019 prices varied between £27 and £20 per sheep depending on lab and numbers.
Scrapie Monitoring Scheme –
SRUC run a scheme on behalf of DEFRA called the Scrapie Monitoring Scheme / Scrapie Monitored flocks (“SMS / SM”). The full rules and requirements are available via the SRUC website on the Premium Sheep and Goat Health Schemes page.
Downloads related to the SMS are available on the SRUC website at https://www.sruc.ac.uk/downloads/120113/premium_sheep_and_goat_health_schemes
If you want to see which SSBA members are SMS, then go to www.psghs.co.uk. Within the scheme there are two categories – Controlled Risk (3 years minimum scrapie free under the scheme rules) and Negligible Risk (7 years minimum). SMS flocks can only buy in animals from the same or a higher category of SMS member or those certified R1 by SRUC.
If you are not SM and want to export sheep (which must be ARR/ARR) or sell sheep into an SMS flock, then the testing must be done by the SRUC and the blood sample has to be taken and sent off by your vet. This is obviously more expensive than self-testing. Forms and prices are available on the SRUC website.
This is necessarily a quick run through a large and complex area. For any queries or other scrapie testing and monitoring questions, your Council contact is Peter Geddes (firstname.lastname@example.org).